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We devised a method of estimating population size of Marbled Murrelets (Brachyramphus marmoratus) found in California?s offshore waters. The method involves determining the distribution of birds from the shore outward to 6,000 m offshore. Applying this distribution to data from boat surveys, we derived population estimates and estimates of sampling...

Several authors have recently discussed the problems with using index methods to estimate trends in population size. Some have expressed the view that index methods should virtually never be used. Others have responded by defending index methods and questioning whether better alternatives exist. We suggest that index methods are often a costeffective component of valid...

Unionidmussels were sampled in the Big South Fork of the Cumberland River, Tennessee and Kentucky, from July to October 1988 with a chain grid of10 l-m2 quadrats. The chain grid was used to define 100-m2 areas along the stream bed by repeatedly moving the10-m2 rectangle upstream. Within each100-m

Densely vegetated environments have hindered collection of basic population parameters on forest-dwelling ungulates. Our objective was to develop a mark-recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black...

During a 5-week study of the Nihoa Millerbird and Nihoa Finch, we censused birds using these techniques: two line transect methods, a variable-distance circular plot method, and spot-mapping of territories (millerbirds only). Densities derived from these methods varied greatly. Due to differences in behavior, it appeared that the two species reacted differently to the...

Accurate knowledge of the number of newly-fledged juveniles offshore is critical to estimates of productivity of the threatened Marbled Murrelet (Brachyramphus marmoratus). We describe a method for collecting productivity data which allows researchers to objectively evaluate age determinations and their effect on juvenile percentages. This has the...

In the west coast region of the United States, fishers (Pekania pennanti) exist in 2 remnant populations?1 in northern California and 1 in the southern Sierra Nevada, California?and 3 reintroduced populations (western Washington, southern Oregon, and northeastern California). The West Coast Distinct Population Segment of fishers encompassing all of...

Hundreds of papers, such as those presented in this volume, are produced annually by workers using various techniques. The purpose of this section is twofold: (1) to provide for readers unfamiliar with counting techniques a handy guide to the most common terms and methods used in the field; and (2) to attempt to set a consensus on the meanings of some terms that are...

Reliable estimates of trends in population size are critical to effective management of landbirds. We propose a standard for considering that landbird populations are adequately monitored: 80% power to detect a 50% decline occurring within 20 years, using a 2-tailed test and a significance level of 0.10, and incorporating effects of potential bias. Our standard also...

We document here a decline of nearly 30% in the Marbled Murrelet (Brachyramphus marmoratus) population of Washington, Oregon, and northern California between 2000 and 2010. The Northwest Forest Plan is an ecosystem-management plan for federal forest lands in the Pacific Northwest of the United States that incorporates monitoring to determine if...

An essential element in the conservation of rare species is the ranking of some aspects of habitat quality. We developed a method to rank the importance of individual habitat patches to Marbled Murrelets (Brachyramphus marmoratus) in 26 old-growth forest stands in northern California, using estimates of stand occupaqcy as an index of nesting activity...

Estimates of survival of nearctic-neotropic migrants have broadened our understanding of life-history variation across taxa and latitudes. Despite the importance of assessing migrants' survival through all phases of their life-cycle, data from their tropical winter ranges are few. In this study we used 14 years of data on captured birds to quantify the influence...

Wildlife management often hinges upon an accurate assessment of population density. Although undeniably useful, many of the traditional approaches to density estimation such as visual counts, livetrapping, or mark?recapture suffer from a suite of methodological and analytical weaknesses. Rare, secretive, or highly mobile species exacerbate these problems through the...

We studied swamp rabbits, white-tailed deer, and small mammals in an old-growth and adjacent second-growth and young-growth bottomland hardwood forest stands in southern Arkansas, August 1991 ? February 1993. Based on average home range size and degree of overlap, minimum and maximum density estimates of swamp rabbits were 31 per km2 (no overlap)...

This paper presents finite element analyses that are being used to analyze and estimate the structural performance of a new product called 3D engineered fiberboard in bending and flat-wise compression applications. A 3x3x2 split-plot experimental design was used to vary geometry configurations to determine their effect on performance properties. The models are based on...

The use of population size as a measure of health of a species has been a very common tool of ornithologists for many years (Lack 1954, 1966; Hutchinson 1978). Methods for surveying population size are detailed in Ralph and Scott (1981), the excellent compendium by Cooperrider and others (1986), and the manual by Koskimies and Vaisanen (1991). Many types of counting...

A modified vehicle-mounted, X-band marine radar system was used to study the movements of marbled murrelets (Brachyramphus marmoratus) at inland and coastal sites in northern California during July. The ability of the radar to discriminate murrelets from other targets, and to estimate abundance was assessed. Murrelets were detected by radar at...

To examine sample size requirements and optimum allocation of effort in point count sampling of bottomland hardwood forests, we computed minimum sample sizes from variation recorded during 82 point counts (May 7-May 16, 1992) from three localities containing three habitat types across three regions of the Mississippi Alluvial Valley (MAV). Also, we estimated the effect...

Fishers (Pekania pennanti) in the west coast states of Washington, Oregon, and California, USA have not recovered from population declines and the United States Fish and Wildlife Service has proposed options for listing them as threatened. Our objectives were to evaluate differences in survival and mortality risk from natural (e.g., predation, disease, injuries,...

Counting birds has a long tradition. Since early in human history, man has noted and recorded the presence, absence, and abundance of birds. This long, and presumably honorable, pursuit that we all engage in, to a greater or lesser extent, is the common currency of many ornithological studies. These studies range from multiple regression analyses of habitat variables...